Hydralazine vs nifedipine for acute hypertensive emergency in pregnancy: a randomized controlled trial

Abstract

Background: There is a paucity of good quality evidence regarding the best therapeutic option for acute control of blood pressure during acute hypertensive emergency of pregnancy.

Objective: We sought to compare the efficacy of intravenously administered hydralazine and oral nifedipine for acute blood pressure control in acute hypertensive emergency of pregnancy.

Study design: In this double-blind, randomized, controlled trial, pregnant women (≥24 weeks period of gestation) with sustained increase in systolic blood pressure of ≥160 mm Hg or diastolic blood pressure of ≥110 mm Hg were randomized to receive intravenous hydralazine injection in doses of 5, 10, 10, and 10 mg and a placebo tablet or oral nifedipine (10 mg tablet up to 4 doses) and intravenous saline injection every 20 minutes until the target blood pressure of 150 mm Hg systolic and ≤100 mm Hg diastolic was achieved. Crossover treatment was administered if the initial treatment failed. The primary outcome of the study was time necessary to achieve target blood pressure. The secondary outcomes were the number of dosages required, adverse maternal and neonatal effects, and perinatal outcome.

Results: From December 2014 through September 2015, we enrolled 60 patients. The median time to achieve target blood pressure was 40 minutes in both groups (intravenous hydralazine and oral nifedipine) (interquartile interval 5 and 40 minutes, respectively, P = .809). The median dose requirement in both groups was 2 (intravenous hydralazine and oral nifedipine) (interquartile range 1 and 2 doses, respectively, P = .625). Intravenous hydralazine was associated with statistically significantly higher occurrence of vomiting (9/30 vs 2/30, respectively, P = .042). No serious adverse maternal or perinatal side effects were witnessed in either group.

Conclusion: Both intravenous hydralazine and oral nifedipine are equally effective in lowering of blood pressure in acute hypertensive emergency of pregnancy.

Keywords: acute hypertensive emergency of pregnancy; blood pressure; critical care; double blind; hypertension; intravenous hydralazine; maternal morbidity; maternal mortality; oral nifedipine; preeclampsia.